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Date:   Sun, 11 Feb 2018 11:59:09 +0100
From:   Adam Borowski <kilobyte@angband.pl>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Joerg Roedel <jroedel@suse.de>, Andy Lutomirski <luto@kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        "H . Peter Anvin" <hpa@zytor.com>, X86 ML <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Juergen Gross <jgross@suse.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>, Jiri Kosina <jkosina@suse.cz>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Brian Gerst <brgerst@gmail.com>,
        David Laight <David.Laight@aculab.com>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Eduardo Valentin <eduval@amazon.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Will Deacon <will.deacon@arm.com>,
        "Liguori, Anthony" <aliguori@amazon.com>,
        Daniel Gruss <daniel.gruss@iaik.tugraz.at>,
        Hugh Dickins <hughd@google.com>,
        Kees Cook <keescook@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Waiman Long <llong@redhat.com>, Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH 00/31 v2] PTI support for x86_32
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On Sat, Feb 10, 2018 at 12:22:59PM -0800, Linus Torvalds wrote:
> On Sat, Feb 10, 2018 at 1:15 AM, Adam Borowski <kilobyte@angband.pl> wrote:
> >
> > Alas, we got some data:
> > https://popcon.debian.org/ says 20% of x86 users have i386 as their main ABI
> > (current; people with popcon installed).
> 
> One of the issues I've seen is that people often simply move a disk
> (or copy an installation) when upgrading machines.

Less skilled users (ie, most of them) had until recently a different hurdle:
the "32-bit" option was shown way too prominently, without an explanation.

> Does Debian make it easy to upgrade to a 64-bit kernel if you have a
> 32-bit install?

Quite easy, yeah.  Crossgrading userspace is not for the faint of the heart,
but changing just the kernel is fine.

> Because if not, then it's entirely possible that a lot
> of people started out with a 32-bit install (maybe they even had a
> 64-bit kernel, but they started when the 32-bit install was the
> default one), and never upgraded their kernel.
> 
> It really should be easy to _just_ upgrade the kernel. But if the
> distro doesn't support it, most people won't do it.

I just realized that, for people who use distro kernels, the right way is a
message during upgrade.  Ie, it's up to the packagers rather than you.

Having a dire-sounding printk, though, would still be nice.


Meow!
-- 
⢀⣴⠾⠻⢶⣦⠀
⣾⠁⢰⠒⠀⣿⡁ Vat kind uf sufficiently advanced technology iz dis!?
⢿⡄⠘⠷⠚⠋⠀                                 -- Genghis Ht'rok'din
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